dont_get_stuck

The check engine light is on in my 2000 cherokee. Only one code comes up which is cylinder 1 misfire. I have changed the spark plugs as well as upgraded to neon injectors and had the ecu cleared several times but that didn't help. Could a bad coil cause only one cylinder to misfire? Any other ideas? I need to get this light off asap. Thanks.

O yea. The jeep idles rough and you can feel the skip at an idle but it seems to drive fine once the throttle is pressed. I don't really know if there is a loss of power because I bought it with the cel light.

tjwalker

Could be the coil pack.

Also would be a good idea to test compression on all cylinders and see if cylinder #1 is out of spec.

Also know that the 2000 came with the factory 0331 cylinder head, which has a known casting defect between cylinders 3-4. This makes it prone to cracking, especially after an overheat.

The #1 symptom of a cracked 0331 head is LOSS OF COOLANT FROM THE RESERVOIR. So your new hobby is keeping an eagle eye on that reservoir for any unexplained drop in level there.

dont_get_stuck

Ok. Its been a while, but I did a compression check and all cylinders are good. The jeep uses no coolant what so ever. I replaced the coil pack with a brand new one from advance. The light is still on for cylinder one, but now I have the code for random multiple misfire. Could I have got a bad coil pack or could it be something else?

tjwalker

I'd verify fuel pressure with a gauge. Should have 49 psi, plus or minus 5 psi.

A marginal fuel pressure issue could create the symptoms/codes you are seeing.

Yes it could be something else, but you must rule fuel delivery in or out at this point.